Apparatuses for introduction into a structure via an opening (e.g. a hole) have been known for many years, and are used for different applications. For example, these apparatuses are known as: drills which are used in mechanical engineering, catheters which are used in medical endoscopy, monitoring devices which are used for various monitoring purposes, etc. In some cases, there is a need to introduce an apparatus along a straight path, and at some later stage to change the path of the introduction to a predetermined curved trajectory in which the device should be stable and its path should be well defined.